Influence of Particle Size on Ecotoxicity of Low-Density Polyethylene Microplastics, with and without Adsorbed Benzo-a-Pyrene, in Clam Scrobicularia plana

Abstract

This study investigated the ecotoxicological effects of differently sized (4–6 µm and 20–25 µm) low-density polyethylene (LDPE) microplastics (MPs), with and without adsorbed benzo-a-pyrene (BaP), in clam Scrobicularia plana. Biomarkers of oxidative stress (superoxide dismutase—SOD; catalase—CAT), biotransformation (glutathione-S-transferases—GST), oxidative damage (lipid peroxidation—LPO) and neurotoxicity (acetylcholinesterase—AChE) were analysed in gills and digestive glands at different time intervals for a total of 14 days of exposure. In order to have a better impact perspective of these contaminants, an integrated biomarker response index (IBR) and Health Index were applied. Biomarker alterations are apparently more related to smaller sized (4–6 µm) MPs in gills and to virgin LDPE MPs in the digestive gland according to IBR results, while the digestive gland was more affected by these MPs according to the health index.

Elucidating the consequences of the co-exposure of microplastics jointly to other pollutants in bivalves: A review

“…From the present review seems that the activity of some enzymes such as CAT are time-dependent to the co-exposure of MPs and PAHs, since in Mediterranean mussels (M. galloprovincialis) the exposure to LDPE and BaP jointly or separately triggered a higher CAT activity in digestive gland after 14 and 28 days of exposure, while after 7 days of exposure all individuals showed similar values with respect to the control group (Pittura et al, 2018;Rodrigues et al, 2022). A reverse time-dependent response was observed in hemocytes from the same species (M. galloprovincialis) since the activity of this enzyme was higher during the first days of the experiment (7 days) and then it is followed by a decrease after 26 days of exposure (González-Soto et al, 2019).…”